Strength and knot security of braided polyester and caprolactone/glycolide suture

Appropriate suture selection is necessary in providing mechanical stability to soft tissue reconstructions. Caprolactone/glycolide (Panacryltrade mark) became a popular suture, possessing excellent handling properties; however, clinical observations questioned the knot security of caprolactone/glycolide. Caprolactone/glycolide is still available on many commercial suture anchor systems. This study compared the security of the knots and ultimate tensile strength of braided caprolactone/glycolide suture to that of a commonly used suture material, braided polyester (Ethibondtrade mark).

Suture knots of No. 2 braided polyester suture and No. 2 braided caprolactone/glycolide suture were submersed in a physiologic saline solution and stressed using a continuous (non-cyclic) load, simulating a single maximal loading event in a clinical setting. Continuous loading was done to achieve clinical suture knot failure (3-mm knot slippage), then continued until catastrophic suture failure (suture breakage) occurred. Ten trials of each suture were tested.

Force required to cause knot slippage of 3 mm was greater for braided polyester than for braided caprolactone/glycolide (p <. 0001, unpaired Students' t-test). Forces resulting in catastrophic failure were greater for braided polyester than braided caprolactone/glycolide (p = .0284, unpaired Students' t-test).

These data have important implications in the selection of suture materials for repair of soft tissue injuries. In the clinical setting, a single maximal loading event may result in suture failure. These data indicate that braided polyester possesses superior in-vitro mechanical properties and suggest that braided polyester may provide greater security in-vivo than braided caprolactone/glycolide suture.